Praetor wrote:
Did a bit of math and here's my results. Click to embiggen the image.
We begin with the 622 meter Excelsior, scaled from her window rows. Sized asis in my file, she's 2363 px. I then scale the Enterprise refit to 2/3 Excelsior size to maintain the relative size difference first put forth at the official, smaller scale. At 1575 px, she's 415 meters long. I scaled the Miranda, TOS Enterprise to match, and for good measure throw in the fourdeck saucer version of the Oberth.
Overall:
Excelsior: @ 622 meters/2363 px & 35 decks
Ent refit: @ 415 meters/1575 px & 33 decks
Miranda: @ 326 meters/1240 px & 19 decks (5 in rollbar pod)
Ent TOS: @ 408 meters/1552 px & 33 decks
Oberth: @ 260 meters/988 px & 17 decks

Having the ships be closer in size doesn't look bad at all  more cohesive as a group.
What peeks my interest in particular is (of course) the size of the TOS Enterprise. Recent developments over in the Shuttlebay Pic thread has caused me to rethink how the shuttlebay (as depicted on the show by the 122' scale model) fits into the vessel and how that in turn can lead to recalculating the likely length of the old girl.
For instance (going by the info in the above mentioned thread) if the allocated space behind the pylons is 89' on a 947' ship then expanding it to fit in the 122' shuttlebay miniature will give a ship of 1298'. However, SHAW's work suggests that model as assembled has even less space than that, leading to a vessel of 1450' or more!
So basically, I am just curious as to how you arrived at your own conclusions, and a ship length of 408 metres (1338 feet)